Field
The invention relates to a method for controlling a driver assistance system.
Description of the Related Art
During the last years driver assistance systems have been rapidly developed in order to increase the comfort for a driver and also the safety of driving. This is in particular important, because the traffic density increased over the years and thus, in everyday driving a driver is frequently faced with truly complex traffic situations. In such situations it is advantageous if the driver is assisted by a driver assistance system so that responsibility for perceiving the traffic situation does not lie with the driver only.
Such driver assistance systems are capable of sensing the environment around a vehicle. In order to do so the vehicles are equipped with sensors like radar or lidar sensors or with image processing systems that include a camera and which are capable of recognizing objects in the environment of the vehicle. Such systems are in most cases mounted on the vehicle in a distributed fashion so that a 360° surveillance around the vehicle is possible. Of course, such a 360° surveillance exceeds any attention a human driver may pay.
Another source of information which can be used by driver assistance systems is a car-to-x communication so that a vehicle in the environment of the host vehicle of the system does not necessarily need to sense any objects in its environment on its own. Based on this information a driver assistance system performs an evaluation of the scene and based on a fixed scheme gives warnings or notifications to the driver. Since the driver assistance systems become more and more advanced vast information has to be presented to the driver in particular when a close cooperation between the driver and the system is necessary. This is for example the case when a semi-automatic driving shall be made where driver and assistance system together solve challenges of the driving task.
In current systems the driver is always the last instance and information is provided for example by presenting an icon so that the driver easily can recognize the reason for the presented warning. Due to improved situation models, prediction models and evaluation of a sensed traffic scene in general the amount of information that is presented to the driver also increases. Thus, the results of the analysis of the traffic situation lead to an unwanted distraction of the driver because he is demanded to check what kind of notification or warning is presented, then to decide if this warning or notification is relevant for his intended further driving behavior and act accordingly. Thus, contrary to the original intention of the driver assistance system the driver may be disturbed and his concentration badly affected.
In order to reduce the bad affect for the driver modern systems use head-up displays which often use some form of augmented reality. Nevertheless, the presented objects may have been recognized by the driver already. Thus, the driver receives an additional warning which is unnecessary but obtrusive and redundant. This might lead to a bad acceptance of such systems and finally the driver may deactivate the systems.
There have been presented some suggestions that use knowledge about a driver attention state which is obtained by monitoring overall awareness versus drowsiness levels of the driver. Alternatively, the viewing angle of the driver or an estimated distraction according to current entertainment usage or cell phone usage may be a basis for a threshold level which is used to determine whether a driver shall be notified or warned. Examples for such approaches can be found in KR 2011/0144720 or DE 10 2012109 297 A1.
Furthermore, it has been described that the driver himself can manually adapt the threshold meaning the risk level when a warning is output by a system. But as described in DE 10 2012 201 934 A1 this is a general setting for the system which does not take account of a current traffic situation of the host vehicle. Up to now there are mainly used general settings which are basically input by a user using a human machine interface of the car which basically consists of touch screens, buttons and control knobs. But the presently known human machine interfaces are not suitable to adapt the performance and the behavior of the system depending on a currently experienced traffic situation. Thus, the input of a general setting regarding risk level for example may either result in the driver feeling upset because of a load of information which is to high or that in cases where assistance would be highly recommended a risk level that is set to a relatively high value will avoid that helpful information is output to the driver.
In EP 1807267 B1 a system for driver assistance is presented which monitors the driving situation and makes suggestions for providing active driving manoeuver assistance. Based on the environment sensing the assistance system detects a particular situation from a pre-defined catalogue of situations like parking, overtaking maneuver, or distance-controlled cruise control. For each element of the catalogue of situations there exists a number of possible suggestions that may be offered by the system depending on the current realization of the situation. The suggestions of the system can be confirmed or rejected by the driver, either actively by speech or control input, or indirectly by performing a driving action which is compatible or incompatible with the suggestion. For the evaluation of the driving situation the driver's attentiveness is taken into account.